Alternating current and direct current charging and discharging power battery system

Abstract

The utility model discloses an AC / DC charging and discharging power battery system, a conversion control circuit comprises a main loop, a conversion loop, a DC loop and a BMS system, a load battery is configured on the main loop, and the DC loop and the conversion loop are integrated in a battery pack to which the load battery belongs; the conversion loop is connected to the main loop in series, the direct current loop is connected to the main loop in series, the direct current loop is connected with the conversion loop in parallel, and the conversion loop and the main loop are electrically connected with the BMS system; an alternating current interface is configured on the conversion loop, and a direct current interface is configured on the direct current loop; the alternating current interface is used for being externally connected with an alternating current power supply to charge the load battery or externally connected with alternating current electric equipment to supply power to the alternating current electric equipment; the direct current interface is used for being externally connected with a direct current power supply to charge the load battery or being externally connected with direct current electric equipment to supply power to the direct current electric equipment.

Description

Technical Field

[0001] This utility model belongs to the field of power battery technology, specifically relating to an AC / DC charging and discharging power battery system. Background Technology

[0002] Electric vehicle sales are accounting for an increasing proportion of total car sales year by year, and the installed capacity of power batteries is also increasing. With the continuous updating of the vehicle's electronic and electrical architecture, the development direction is gradually moving towards greater integration. Therefore, power batteries also need to improve their electronic and electrical architecture to further adapt to the development of the industry.

[0003] Traditional power batteries typically consist of three main components: battery cells, battery management system (BMS), and battery circuit breaker unit. They can output DC power through a high-voltage interface. The motor controller on the vehicle converts the DC power output from the power battery into AC power to drive the three-phase motor. At the same time, during charging, an external charger is required to convert the AC power back into DC power before inputting it into the power battery. For example, the current conversion circuit, microcontroller, and vehicle disclosed in application number CN202020203019.7 still rely on external integrated circuits to achieve AC-DC conversion.

[0004] Therefore, if external energy conversion devices can be integrated into the power battery pack, the integration level of the power battery pack will be significantly improved. Utility Model Content

[0005] The purpose of this invention is to provide an AC / DC charging and discharging power battery system. Based on the BMS system, an energy conversion circuit is designed to convert AC power to DC power within the battery pack, thereby improving the functionality and integration of the power battery pack. This eliminates the need for external equipment and reduces costs.

[0006] The technical solution adopted by this utility model to solve its technical problem is to propose an AC / DC charging and discharging power battery system, including a main circuit, a conversion circuit, a DC circuit and a BMS system. The main circuit is equipped with a load battery. The conversion circuit is connected in series with the main circuit, the DC circuit is connected in series with the main circuit, the DC circuit and the conversion circuit are connected in parallel, and the conversion circuit, the main circuit and the BMS system are electrically connected. The conversion circuit is used for the conversion of AC power and DC power.

[0007] The conversion circuit is equipped with an AC interface, and the DC circuit is equipped with a DC interface; the AC interface is used to connect an external AC power source to charge the load battery, or to connect an external AC power device to power the AC power device; the DC interface is used to connect an external DC power source to charge the load battery, or to connect an external DC power device to power the DC power device.

[0008] During charging, the AC power is converted to DC power through the conversion circuit, or the DC power is used to charge the load battery through the DC circuit.

[0009] During discharge, the load battery converts DC power into AC power through the DC circuit or the conversion circuit for discharge.

[0010] The DC circuit and the conversion circuit are integrated into the battery pack to which the load battery belongs.

[0011] Furthermore, a main relay KM1 is connected in series in the main circuit, the main relay KM1 is connected in series with the load battery, and the main relay KM1 is electrically connected to the BMS system.

[0012] Furthermore, it also includes a pre-charge circuit, which is connected in parallel to both ends of the main relay KM1; the pre-charge circuit includes a pre-charge relay KM2 and a pre-charge resistor R, the pre-charge resistor R is connected in series with the pre-charge relay KM2, and the pre-charge relay KM2 is electrically connected to the BMS system.

[0013] Furthermore, the DC circuit also includes a fuse Fu, which is connected in series with the DC interface U3 and is connected in series between the positive terminal of the battery load and the DC interface U3.

[0014] Furthermore, the conversion circuit includes three bridge arms connected in parallel and a filter capacitor C. The three bridge arms are connected in parallel and then connected in series with the main circuit. The filter capacitor C is connected in series with the main circuit. The three bridge arms are connected in parallel and then connected in parallel with the filter capacitor C.

[0015] Furthermore, the three bridge arms include a first bridge path, a second bridge path, and a third bridge path. A first switch and a second switch are connected in series on the first bridge path, a third switch and a fourth switch are connected in series on the second bridge path, and a fifth switch and a sixth switch are connected in series on the third bridge path. The first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are respectively electrically connected to the BMS system.

[0016] Furthermore, a switching relay KM3 is connected in series between the first bridge circuit and the second bridge circuit, and the switching relay KM3 is electrically connected to the BMS system.

[0017] Furthermore, the AC interface includes a three-phase power interface and a single-phase power interface.

[0018] Furthermore, the three-phase electrical interface includes a first phase, a second phase, and a third phase. The first phase is connected between the first switch and the second switch, the second phase is connected between the third switch and the fourth switch, and the third phase is connected between the fifth switch and the sixth switch. The BMS system controls the on / off state of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch to form a three-phase full-bridge circuit.

[0019] Furthermore, the single-phase electrical interface includes a fourth phase and a fifth phase. The fourth phase is connected to the second phase, and the fifth phase is connected to the third phase. The BMS system controls the switching on and off of the third, fourth, fifth, and sixth switches to form a single-phase full-bridge circuit.

[0020] During charging and discharging, the state switching of the control circuit by the BMS system realizes the AC-DC conversion within the battery pack; it does not rely on external integrated circuits and has a high degree of integration.

[0021] The beneficial effects of this utility model are as follows:

[0022] This invention proposes an AC / DC charging and discharging power battery system. Based on a BMS system, a conversion circuit is designed within the battery pack to convert AC power to DC power within the battery pack. During charging and discharging, the BMS system controls the conversion circuit to achieve AC / DC conversion within the battery pack, eliminating the need for external integrated circuits, resulting in a high degree of integration and reduced costs.

[0023] This invention uses the BMS system as the control device for the entire battery pack, connects to external devices for communication, and controls the internal control circuits and circuit breaker units of the battery pack. This allows the power battery pack to output both high-voltage DC power and three-phase power, while also having a variety of charging interface power types. It does not rely on external devices, greatly facilitating charging requirements.

[0024] It can convert the high-voltage DC power from the battery pack into three-phase power. Through communication between the BMS and the motor controller, the converted three-phase power can directly drive the three-phase motor. At the same time, it is equipped with an external high-voltage DC power interface to supply power to equipment using high-voltage DC power in the vehicle. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present invention, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without any inventive effort.

[0026] Figure 1 This is a structural diagram of an AC / DC charging and discharging power battery system according to an embodiment of the present invention. Detailed Implementation

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model and the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. Furthermore, the design orientation only indicates the relative positional relationship between the components, not the absolute positional relationship.

[0028] This utility model embodiment provides an AC / DC charging and discharging power battery system. Please refer to [link / reference]. Figure 1 It includes a main circuit, a conversion circuit, a DC circuit, and a BMS system. The main circuit is equipped with a load battery. The conversion circuit is connected in series with the main circuit, the DC circuit is connected in series with the main circuit, the DC circuit and the conversion circuit are connected in parallel, and the main circuit, the conversion circuit and the BMS system are electrically connected. The conversion circuit is used for the conversion of AC and DC power.

[0029] The conversion circuit is equipped with an AC interface, and the DC circuit is equipped with a DC interface; the AC interface is used to connect an external AC power source to charge the load battery, or to connect an external AC power device to power the AC power device; the DC interface is used to connect an external DC power source to charge the load battery, or to connect an external DC power device to power the DC power device.

[0030] For example, AC electrical equipment may include three-phase motors, vehicle-mounted AC electrical appliances, etc., while DC electrical equipment may include vehicle-mounted DC electrical appliances, external discharge devices, etc., and the AC and DC power sources may be the power grid, etc.

[0031] Specifically, during charging, the AC power is converted to DC power or a DC circuit is used to charge the load battery; during discharging, the load battery is converted to AC power through a DC circuit or a conversion circuit to discharge.

[0032] The DC circuit and conversion circuit are integrated into the battery pack of the load battery, which can complete the AC-DC conversion within the battery pack, allowing the battery pack to be used independently without the need for external devices or integrated circuits to achieve AC-DC conversion.

[0033] In this application, the AC interface includes a three-phase power interface U1 and a single-phase power interface U2, and a DC interface U3 is configured on the DC circuit; the three-phase power interface U1, the single-phase power interface U2, and the DC interface U3 are all charging and discharging interfaces, and a single interface can be selected for charging or discharging according to the actual situation.

[0034] Figure 1 In the diagram, dashed lines indicate direct or indirect electrical connections for communication, data acquisition, and control, while straight lines indicate circuit electrical connections. Additionally, dashed frames are provided around the three-phase interface U1, single-phase interface U2, and DC interface U3, as well as around the energy conversion circuit, to distinguish them.

[0035] In this application, a load battery is configured on the main circuit. The load battery can be composed of multiple cells, with the positive and negative terminals marked as shown in the diagram. Figure 1 As shown in the diagram. Simultaneously, a main relay KM1 is connected in series in the main circuit. The main relay KM1 is connected in series with the load battery and is electrically connected to the BMS system. The BMS system controls the closing / opening of the main relay KM1, thereby controlling the on / off state of the main circuit.

[0036] A pre-charge circuit can also be configured on the main circuit to realize the pre-charge function; the pre-charge circuit is connected in parallel to the two ends of the main relay KM1, such as... Figure 1 As shown in the figure; specifically, the pre-charge circuit includes a pre-charge relay KM2 and a pre-charge resistor R. The pre-charge resistor R is connected in series with the pre-charge relay KM2, and the charging current is limited by the pre-charge resistor R. The pre-charge relay KM2 is electrically connected to the BMS system, and the BMS system controls the closing / opening of the pre-charge relay KM2, thereby controlling the on / off state of the pre-charge circuit.

[0037] In the embodiments of this application, a fuse Fu is also configured on the DC circuit to protect the DC circuit; the fuse Fu is connected in series with the DC interface U3; specifically, the fuse Fu is connected in series between the positive terminal of the battery load and the DC interface U3, such as... Figure 1 As shown in the image.

[0038] In the embodiments of this application, the conversion circuit includes three bridge arms connected in parallel and a filter capacitor C. The three bridge arms are connected in parallel and then in series with the main circuit. The filter capacitor C is connected in series with the main circuit. The three bridge arms are connected in parallel and then in parallel with the filter capacitor C. Figure 1 As shown in the image.

[0039] Specifically, the three bridge arms can be designated as the first bridge circuit, the second bridge circuit, and the third bridge circuit. Each bridge circuit is equipped with an electronically controlled switch, such as an IGBT, to form a full-bridge circuit and realize AC / DC conversion.

[0040] For example, a first switch IGBT1 and a second switch IGBT2 are connected in series on the first bridge circuit, a third switch IGBT3 and a fourth switch IGBT4 are connected in series on the second bridge circuit, and a fifth switch IGBT5 and a sixth switch IGBT6 are connected in series on the third bridge circuit. The first switch IGBT1, the second switch IGBT2, the third switch IGBT3, the fourth switch IGBT4, the fifth switch IGBT5, and the sixth switch IGBT6 are electrically connected to the BMS system.

[0041] In one specific embodiment, a three-phase full-bridge circuit is constructed based on all IGBTs on the three bridge arms. It is suitable for three-phase AC power and can convert three-phase AC power into high-voltage DC power, or vice versa.

[0042] For details, please refer to Figure 1 The three-phase electrical interface U1 includes a first phase A, a second phase B, and a third phase C. The first phase A is connected between the first switch IGBT1 and the second switch IGBT2, the second phase B is connected between the third switch IGBT3 and the fourth switch IGBT4, and the third phase C is connected between the fifth switch IGBT5 and the sixth switch IGBT6. The BMS system controls the switching of the first switch IGBT1, the second switch IGBT2, the third switch IGBT3, the fourth switch IGBT4, the fifth switch IGBT5, and the sixth switch IGBT6 to form a three-phase full-bridge circuit.

[0043] In another specific embodiment, a single-phase full-bridge circuit is constructed based on all IGBTs on the two bridge arms. It is suitable for single-phase AC power and can convert single-phase AC power into high-voltage DC power, or vice versa.

[0044] For details, please refer to Figure 1 The single-phase electrical interface U2 includes a fourth phase N and a fifth phase L. The fourth phase N is connected between the third switch IGBT3 and the fourth switch IGBT4, and the fifth phase L is connected between the fifth switch IGBT5 and the fifth switch IGBT6. The BMS system controls the switching on and off of the third switch IGBT3, the fourth switch IGBT4, the fifth switch IGBT5, and the sixth switch IGBT6 to form a single-phase full-bridge circuit.

[0045] It is feasible to directly connect the fourth phase N to the second phase B, and the fifth phase L to the third phase C, to avoid redundant wiring. Figure 1 As shown in the diagram. Additionally, the first inductor l1, the second inductor l2, and the third inductor l3 can be configured on the first phase A, the second phase B, and the third phase C, respectively, with the configuration positions as shown. Figure 1 As shown in the image.

[0046] Furthermore, a switching relay KM3 can be connected in series between the first bridge circuit and the second bridge circuit. The switching relay KM3 is electrically connected to the BMS system, and the BMS system controls the closing / opening of the switching relay KM3, thereby controlling the switching between the single-phase full-bridge circuit and the three-phase full-bridge circuit. When the switching relay KM3 is closed, the conditions for the formation of a three-phase full-bridge circuit are met; when the switching relay KM3 is open, the conditions for the formation of a single-phase full-bridge circuit are met.

[0047] The control circuit described in this application is based on a BMS system design and is integrated inside the battery pack. It can be integrated with the BMS system on the same circuit board to realize energy conversion inside the power battery pack, namely AC-DC conversion.

[0048] During the discharge phase, the high-voltage DC power from the battery pack is converted into three-phase power through communication between the BMS system and the motor controller, enabling the converted three-phase power to directly drive the three-phase motor. At the same time, an external high-voltage DC power interface is provided to supply power to equipment using high-voltage DC power in the vehicle. In addition, vehicles with discharge capabilities can convert the high-voltage DC power from the battery pack into permissible discharge types, such as single-phase AC or DC power, to achieve external discharge.

[0049] During charging, the following strategies can be employed:

[0050] When the external connection input is three-phase power, the charging interface communicates with the BMS system to transmit the connection type and interface definition. Charging is performed through the three-phase power interface U1. The BMS system controls all IGBTs (specifically IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, and IGBT6) to work, converting the three-phase power into high-voltage DC power, and controls the relay to close, inputting the high-voltage DC power to the battery.

[0051] Specifically, the BMS system controls the pre-charge relay KM2 to close, enabling the pre-charge function. After pre-charging, it first controls the main relays KM1 and KM3 to close, and then controls the pre-charge relay KM2 to open. At this time, the main circuit is connected. The BMS system can control the IGBTs to switch on and off at high speed by applying PWN to the base of the IGBTs in the three-phase full-bridge circuit, realizing the conversion of AC power to DC power (charging) or AC power to DC power (discharging). Charging and discharging can be performed through the three-phase power interface U1.

[0052] When the external connection input is single-phase power, the charging interface communicates with the BMS system to transmit the connection type and interface definition. Charging is performed through the single-phase power interface U2. The BMS system controls the corresponding connected IGBTs (specifically IGBT3, IGBT4, IGBT5, and IGBT6) to work, converting the single-phase power into high-voltage DC power, and controls the relay to close, inputting the high-voltage DC power to the load battery for charging.

[0053] Specifically, the BMS system can achieve the pre-charge function by controlling the pre-charge relay KM2 to close. After the pre-charge is completed, it first controls the main relay KM1 to close, and then controls the pre-charge relay KM2 to open. At this time, the main circuit is connected. The BMS system can control the IGBT to switch on and off at high speed by applying PWM to the base of the IGBT in the single-phase full-bridge circuit, so as to convert AC power into DC power (charging) or DC power into AC power (discharging). Charging and discharging can be performed through the single-phase power interface U2.

[0054] When the external connection input is high-voltage DC, the charging interface communicates with the BMS system to transmit the connection type and interface definition, and charges through the DC interface U3. It directly controls the relay to close and inputs high-voltage DC to the load battery for charging.

[0055] Specifically, the BMS system can achieve the pre-charge function by controlling the pre-charge relay KM2 to close. After the pre-charge is completed, it first controls the main relay KM1 to close, and then controls the pre-charge relay KM2 to open. At this time, the main circuit is connected, and charging and discharging can be performed through the DC interface U3.

[0056] Therefore, the BMS system is used as the control device for the entire battery pack. It connects to external devices to communicate and controls the internal control circuits and the battery pack circuit breaker unit. This allows the power battery pack to output high-voltage DC power, three-phase power, and single-phase power. It also has a variety of charging interface power types and does not depend on external devices, which greatly facilitates charging requirements.

[0057] The battery pack circuit breaker unit can be used to control the on / off state of the DC and AC interfaces. Figure 1 The switch, not shown, could be a controllable switch, such as an electromagnetic relay. This controllable switch is electrically connected to the BMS system and is managed by the BMS system. When high-voltage DC power needs to be output, the DC interface is on; otherwise, it is off. When AC power needs to be output, the AC interface is on; otherwise, it is off. It can be understood that AC and DC power can be output simultaneously, in which case both the AC and DC interfaces are on.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0059] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. An AC / DC charging and discharging power battery system, characterized in that, The system includes a main circuit, a conversion circuit, a DC circuit, and a BMS system. A load battery is configured on the main circuit. The DC circuit and the conversion circuit are integrated within the battery pack of the load battery. The conversion circuit is connected in series to the main circuit, and the DC circuit is also connected in series to the main circuit. The DC circuit and the conversion circuit are connected in parallel. The conversion circuit, the main circuit, and the BMS system are electrically connected. The conversion circuit is used for converting AC to DC power. The conversion circuit is equipped with an AC interface, and the DC circuit is equipped with a DC interface; the AC interface is used to connect an external AC power source to charge the load battery, or to connect an external AC power device to power the AC power device; the DC interface is used to connect an external DC power source to charge the load battery, or to connect an external DC power device to power the DC power device.

2. The AC / DC charging and discharging power battery system according to claim 1, characterized in that, A main relay is connected in series in the main circuit. The main relay is connected in series with the load battery and is electrically connected to the BMS system.

3. The AC / DC charging and discharging power battery system according to claim 2, characterized in that, It also includes a pre-charging circuit, which is connected in parallel to both ends of the main relay; the pre-charging circuit includes a pre-charging relay and a pre-charging resistor, the pre-charging resistor is connected in series with the pre-charging relay, and the pre-charging relay is electrically connected to the BMS system.

4. The AC / DC charging and discharging power battery system according to claim 1, characterized in that, The DC circuit also includes a fuse connected in series with the DC interface, and the fuse is connected in series between the positive terminal of the load battery and the DC interface.

5. The AC / DC charging and discharging power battery system according to claim 1, characterized in that, The conversion circuit includes three bridge arms connected in parallel and a filter capacitor. The three bridge arms are connected in parallel and then in series with the main circuit. The filter capacitor is connected in series with the main circuit, and the three bridge arms are connected in parallel with the filter capacitor.

6. The AC / DC charging and discharging power battery system according to claim 5, characterized in that, The three bridge arms include a first bridge path, a second bridge path, and a third bridge path. A first switch and a second switch are connected in series on the first bridge path, a third switch and a fourth switch are connected in series on the second bridge path, and a fifth switch and a sixth switch are connected in series on the third bridge path. The first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are electrically connected to the BMS system.

7. The AC / DC charging and discharging power battery system according to claim 6, characterized in that, A switching relay is connected in series between the first bridge circuit and the second bridge circuit, and the switching relay is electrically connected to the BMS system.

8. The AC / DC charging and discharging power battery system according to claim 6, characterized in that, The AC interface includes a three-phase power interface and a single-phase power interface.

9. The AC / DC charging and discharging power battery system according to claim 8, characterized in that, The three-phase electrical interface includes a first phase, a second phase, and a third phase. The first phase is connected between the first switch and the second switch, the second phase is connected between the third switch and the fourth switch, and the third phase is connected between the fifth switch and the sixth switch. The BMS system controls the on / off state of the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch to form a three-phase full-bridge circuit.

10. The AC / DC charging and discharging power battery system according to claim 9, characterized in that, The single-phase electrical interface includes a fourth phase and a fifth phase. The fourth phase is connected to the second phase, and the fifth phase is connected to the third phase. The BMS system controls the on / off state of the third, fourth, fifth, and sixth switches to form a single-phase full-bridge circuit.

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